There have been electric charging stations that perform supply of power (referred to as power feeding) to electric vehicles. Electric vehicles can be fed with power in the electric charging stations so as to be charged. In the electric charging stations, power meters are provided to measure amounts of power (power amounts) supplied from an electric power company and periods of time taken for supplying power. The power meters measure power supplied to electric vehicles, and on the basis of the measured power, users of the electric vehicles are charged to pay for charging on the electric vehicles (referred to as charging rates).
The owners of the electric charging stations have been designated as consumers corresponding to the power meters for measuring power supplied in the electric charging stations, regardless of the users of the electric vehicles actually receiving supply of power from the electric charging stations. This type of power feeding business has a payment model in which the users of the electric vehicles pay charging rates to the owners of the electric charging stations and the owners of the electric charging stations have paid utility rates for use of power to the electric power company with which the owners of the electric charging stations make contracts, and it has been difficult to implement other payment models. As an example of other payment models, there is a payment model in which users of electric vehicles directly pay all or a part of the charging rates to electric power companies with which the users make contracts as consumers. In this payment model, the electric power companies with which the users of the electric vehicles make contracts may be different from electric power companies that supply power to electric charging stations. In order to make it possible to realize this payment model, it has been required to make it possible to dynamically and safely change a correspondence relation between power meters and consumers.